1. Field Of The Invention
The present invention relates to the field of integrated circuit testing devices and more specifically to a probe card and a probe device for testing integrated circuit wafers.
2. Prior Art
Several hundred distinct semiconductor integrated circuits are manufactured in a single wafer of semiconductor material and are later cut out of the wafer in the form of semiconductor chips. Each of the integrated circuits while in wafer form or in chip form must be tested. U.S. Pat. No. 4,623,839; U.S. Pat. No. 3,702,439; and U.S. Pat. No. 3,849,728 all disclose probe cards for testing integrated circuits in either chip or wafer form. Such cards generally consist of a printed circuit board having a central opening providing access to the chip to be tested together with a series of spaced conductive individual probe assemblies arranged in a ring around the opening. Each probe assembly consists of a probe body connected to a respective conductive line on the board and a flexible metallic needle or blade extending towards the center of the opening. The blade is adapted to contact selected parts on the chip being tested so that electrical signals may be transmitted to the chip under test.
U.S. Pat. No. 4,161,692, teaches a ceramic probe support provided with a compensating circuit thereon which compensates or offsets undesirable impedance characteristics associated with long circuit paths between the probe member and the test equipment. This patent indicates that the construction of the support is such as to enhance the local capacitance characteristic to provide greater circuit isolation due to high surface resistivity, and to minimize the capacitive effect with the probe members, thus allowing both high frequency input signals to be used and the monitoring of high frequency output signals. However, as the frequency characteristics of the applied signals continues to increase, i.e. over 100 MHz, and as greater numbers of circuits switch simultaneously, the type of devices shown in U.S. Pat. No. 4,161,692 begin to fail and cannot carry such high frequency signals without degradation.
It therefore became necessary to create a new probe assembly which would provide power decoupling when the frequencies are greater than 100 MHz.